/* Block-relocating memory allocator. Copyright (C) 1993, 1995 Free Software Foundation, Inc.This file is part of GNU Emacs.GNU Emacs is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2, or (at your option)any later version.GNU Emacs is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Emacs; see the file COPYING. If not, write tothe Free Software Foundation, Inc., 59 Temple Place - Suite 330,Boston, MA 02111-1307, USA. *//* NOTES: Only relocate the blocs necessary for SIZE in r_alloc_sbrk, rather than all of them. This means allowing for a possible hole between the first bloc and the end of malloc storage. */#ifdef emacs#include <config.h>#include "lisp.h" /* Needed for VALBITS. */#undef NULL/* The important properties of this type are that 1) it's a pointer, and 2) arithmetic on it should work as if the size of the object pointed to has a size of 1. */#if 0 /* Arithmetic on void* is a GCC extension. */#ifdef __STDC__typedef void *POINTER;#else#ifdef HAVE_CONFIG_H#include "config.h"#endiftypedef char *POINTER;#endif#endif /* 0 *//* Unconditionally use char * for this. */typedefchar*POINTER;typedefunsignedlongSIZE;/* Declared in dispnew.c, this version doesn't screw up if regions overlap. */externvoidsafe_bcopy();externint__malloc_extra_blocks;#else /* not emacs */#include <stddef.h>typedefsize_tSIZE;typedefvoid*POINTER;#include <unistd.h>#include <malloc.h>#include <string.h>#define safe_bcopy(x, y, z) memmove (y, x, z)#define bzero(x, len) memset (x, 0, len)#endif /* not emacs */#include "getpagesize.h"#define NIL ((POINTER) 0)/* A flag to indicate whether we have initialized ralloc yet. For Emacs's sake, please do not make this local to malloc_init; on some machines, the dumping procedure makes all static variables read-only. On these machines, the word static is #defined to be the empty string, meaning that r_alloc_initialized becomes an automatic variable, and loses its value each time Emacs is started up. */staticintr_alloc_initialized=0;staticvoidr_alloc_init();/* Declarations for working with the malloc, ralloc, and system breaks. *//* Function to set the real break value. */staticPOINTER(*real_morecore)();/* The break value, as seen by malloc. */staticPOINTERvirtual_break_value;/* The address of the end of the last data in use by ralloc, including relocatable blocs as well as malloc data. */staticPOINTERbreak_value;/* This is the size of a page. We round memory requests to this boundary. */staticintpage_size;/* Whenever we get memory from the system, get this many extra bytes. This must be a multiple of page_size. */staticintextra_bytes;/* Macros for rounding. Note that rounding to any value is possible by changing the definition of PAGE. */#define PAGE (getpagesize ())#define ALIGNED(addr) (((unsigned long int) (addr) & (page_size - 1)) == 0)#define ROUNDUP(size) (((unsigned long int) (size) + page_size - 1) \ & ~(page_size - 1))#define ROUND_TO_PAGE(addr) (addr & (~(page_size - 1)))#define MEM_ALIGN sizeof(double)#define MEM_ROUNDUP(addr) (((unsigned long int)(addr) + MEM_ALIGN - 1) \ & ~(MEM_ALIGN - 1))/* Data structures of heaps and blocs. *//* The relocatable objects, or blocs, and the malloc data both reside within one or more heaps. Each heap contains malloc data, running from `start' to `bloc_start', and relocatable objects, running from `bloc_start' to `free'. Relocatable objects may relocate within the same heap or may move into another heap; the heaps themselves may grow but they never move. We try to make just one heap and make it larger as necessary. But sometimes we can't do that, because we can't get contiguous space to add onto the heap. When that happens, we start a new heap. */typedefstructheap{structheap*next;structheap*prev;/* Start of memory range of this heap. */POINTERstart;/* End of memory range of this heap. */POINTERend;/* Start of relocatable data in this heap. */POINTERbloc_start;/* Start of unused space in this heap. */POINTERfree;/* First bloc in this heap. */structbp*first_bloc;/* Last bloc in this heap. */structbp*last_bloc;}*heap_ptr;#define NIL_HEAP ((heap_ptr) 0)#define HEAP_PTR_SIZE (sizeof (struct heap))/* This is the first heap object. If we need additional heap objects, each one resides at the beginning of the space it covers. */staticstructheapheap_base;/* Head and tail of the list of heaps. */staticheap_ptrfirst_heap,last_heap;/* These structures are allocated in the malloc arena. The linked list is kept in order of increasing '.data' members. The data blocks abut each other; if b->next is non-nil, then b->data + b->size == b->next->data. An element with variable==NIL denotes a freed block, which has not yet been collected. They may only appear while r_alloc_freeze > 0, and will be freed when the arena is thawed. Currently, these blocs are not reusable, while the arena is frozen. Very inefficient. */typedefstructbp{structbp*next;structbp*prev;POINTER*variable;POINTERdata;SIZEsize;POINTERnew_data;/* temporarily used for relocation */structheap*heap;/* Heap this bloc is in. */}*bloc_ptr;#define NIL_BLOC ((bloc_ptr) 0)#define BLOC_PTR_SIZE (sizeof (struct bp))/* Head and tail of the list of relocatable blocs. */staticbloc_ptrfirst_bloc,last_bloc;staticintuse_relocatable_buffers;/* If >0, no relocation whatsoever takes place. */staticintr_alloc_freeze_level;/* Functions to get and return memory from the system. *//* Find the heap that ADDRESS falls within. */staticheap_ptrfind_heap(address)POINTERaddress;{heap_ptrheap;for(heap=last_heap;heap;heap=heap->prev){if(heap->start<=address&&address<=heap->end)returnheap;}returnNIL_HEAP;}/* Find SIZE bytes of space in a heap. Try to get them at ADDRESS (which must fall within some heap's range) if we can get that many within one heap. If enough space is not presently available in our reserve, this means getting more page-aligned space from the system. If the returned space is not contiguous to the last heap, allocate a new heap, and append it obtain does not try to keep track of whether space is in use or not in use. It just returns the address of SIZE bytes that fall within a single heap. If you call obtain twice in a row with the same arguments, you typically get the same value. to the heap list. It's the caller's responsibility to keep track of what space is in use. Return the address of the space if all went well, or zero if we couldn't allocate the memory. */staticPOINTERobtain(address,size)POINTERaddress;SIZEsize;{heap_ptrheap;SIZEalready_available;/* Find the heap that ADDRESS falls within. */for(heap=last_heap;heap;heap=heap->prev){if(heap->start<=address&&address<=heap->end)break;}if(!heap)abort();/* If we can't fit SIZE bytes in that heap, try successive later heaps. */while(heap&&address+size>heap->end){heap=heap->next;if(heap==NIL_HEAP)break;address=heap->bloc_start;}/* If we can't fit them within any existing heap, get more space. */if(heap==NIL_HEAP){POINTERnew=(*real_morecore)(0);SIZEget;already_available=(char*)last_heap->end-(char*)address;if(new!=last_heap->end){/* Someone else called sbrk. Make a new heap. */heap_ptrnew_heap=(heap_ptr)MEM_ROUNDUP(new);POINTERbloc_start=(POINTER)MEM_ROUNDUP((POINTER)(new_heap+1));if((*real_morecore)(bloc_start-new)!=new)return0;new_heap->start=new;new_heap->end=bloc_start;new_heap->bloc_start=bloc_start;new_heap->free=bloc_start;new_heap->next=NIL_HEAP;new_heap->prev=last_heap;new_heap->first_bloc=NIL_BLOC;new_heap->last_bloc=NIL_BLOC;last_heap->next=new_heap;last_heap=new_heap;address=bloc_start;already_available=0;}/* Add space to the last heap (which we may have just created). Get some extra, so we can come here less often. */get=size+extra_bytes-already_available;get=(char*)ROUNDUP((char*)last_heap->end+get)-(char*)last_heap->end;if((*real_morecore)(get)!=last_heap->end)return0;last_heap->end+=get;}returnaddress;}/* Return unused heap space to the system if there is a lot of unused space now. This can make the last heap smaller; it can also eliminate the last heap entirely. */staticvoidrelinquish(){registerheap_ptrh;intexcess=0;/* Add the amount of space beyond break_value in all heaps which have extend beyond break_value at all. */for(h=last_heap;h&&break_value<h->end;h=h->prev){excess+=(char*)h->end-(char*)((break_value<h->bloc_start)?h->bloc_start:break_value);}if(excess>extra_bytes*2&&(*real_morecore)(0)==last_heap->end){/* Keep extra_bytes worth of empty space. And don't free anything unless we can free at least extra_bytes. */excess-=extra_bytes;if((char*)last_heap->end-(char*)last_heap->bloc_start<=excess){/* This heap should have no blocs in it. */if(last_heap->first_bloc!=NIL_BLOC||last_heap->last_bloc!=NIL_BLOC)abort();/* Return the last heap, with its header, to the system. */excess=(char*)last_heap->end-(char*)last_heap->start;last_heap=last_heap->prev;last_heap->next=NIL_HEAP;}else{excess=(char*)last_heap->end-(char*)ROUNDUP((char*)last_heap->end-excess);last_heap->end-=excess;}if((*real_morecore)(-excess)==0)abort();}}/* Return the total size in use by relocating allocator, above where malloc gets space. */longr_alloc_size_in_use(){returnbreak_value-virtual_break_value;}/* The meat - allocating, freeing, and relocating blocs. *//* Find the bloc referenced by the address in PTR. Returns a pointer to that block. */staticbloc_ptrfind_bloc(ptr)POINTER*ptr;{registerbloc_ptrp=first_bloc;while(p!=NIL_BLOC){if(p->variable==ptr&&p->data==*ptr)returnp;p=p->next;}returnp;}/* Allocate a bloc of SIZE bytes and append it to the chain of blocs. Returns a pointer to the new bloc, or zero if we couldn't allocate memory for the new block. */staticbloc_ptrget_bloc(size)SIZEsize;{registerbloc_ptrnew_bloc;registerheap_ptrheap;if(!(new_bloc=(bloc_ptr)malloc(BLOC_PTR_SIZE))||!(new_bloc->data=obtain(break_value,size))){if(new_bloc)free(new_bloc);return0;}break_value=new_bloc->data+size;new_bloc->size=size;new_bloc->next=NIL_BLOC;new_bloc->variable=(POINTER*)NIL;new_bloc->new_data=0;/* Record in the heap that this space is in use. */heap=find_heap(new_bloc->data);heap->free=break_value;/* Maintain the correspondence between heaps and blocs. */new_bloc->heap=heap;heap->last_bloc=new_bloc;if(heap->first_bloc==NIL_BLOC)heap->first_bloc=new_bloc;/* Put this bloc on the doubly-linked list of blocs. */if(first_bloc){new_bloc->prev=last_bloc;last_bloc->next=new_bloc;last_bloc=new_bloc;}else{first_bloc=last_bloc=new_bloc;new_bloc->prev=NIL_BLOC;}returnnew_bloc;}/* Calculate new locations of blocs in the list beginning with BLOC, relocating it to start at ADDRESS, in heap HEAP. If enough space is not presently available in our reserve, call obtain for more space. Store the new location of each bloc in its new_data field. Do not touch the contents of blocs or break_value. */staticintrelocate_blocs(bloc,heap,address)bloc_ptrbloc;heap_ptrheap;POINTERaddress;{registerbloc_ptrb=bloc;/* No need to ever call this if arena is frozen, bug somewhere! */if(r_alloc_freeze_level)abort();while(b){/* If bloc B won't fit within HEAP, move to the next heap and try again. */while(heap&&address+b->size>heap->end){heap=heap->next;if(heap==NIL_HEAP)break;address=heap->bloc_start;}/* If BLOC won't fit in any heap, get enough new space to hold BLOC and all following blocs. */if(heap==NIL_HEAP){registerbloc_ptrtb=b;registerSIZEs=0;/* Add up the size of all the following blocs. */while(tb!=NIL_BLOC){if(tb->variable)s+=tb->size;tb=tb->next;}/* Get that space. */address=obtain(address,s);if(address==0)return0;heap=last_heap;}/* Record the new address of this bloc and update where the next bloc can start. */b->new_data=address;if(b->variable)address+=b->size;b=b->next;}return1;}/* Reorder the bloc BLOC to go before bloc BEFORE in the doubly linked list. This is necessary if we put the memory of space of BLOC before that of BEFORE. */staticvoidreorder_bloc(bloc,before)bloc_ptrbloc,before;{bloc_ptrprev,next;/* Splice BLOC out from where it is. */prev=bloc->prev;next=bloc->next;if(prev)prev->next=next;if(next)next->prev=prev;/* Splice it in before BEFORE. */prev=before->prev;if(prev)prev->next=bloc;bloc->prev=prev;before->prev=bloc;bloc->next=before;}/* Update the records of which heaps contain which blocs, starting with heap HEAP and bloc BLOC. */staticvoidupdate_heap_bloc_correspondence(bloc,heap)bloc_ptrbloc;heap_ptrheap;{registerbloc_ptrb;/* Initialize HEAP's status to reflect blocs before BLOC. */if(bloc!=NIL_BLOC&&bloc->prev!=NIL_BLOC&&bloc->prev->heap==heap){/* The previous bloc is in HEAP. */heap->last_bloc=bloc->prev;heap->free=bloc->prev->data+bloc->prev->size;}else{/* HEAP contains no blocs before BLOC. */heap->first_bloc=NIL_BLOC;heap->last_bloc=NIL_BLOC;heap->free=heap->bloc_start;}/* Advance through blocs one by one. */for(b=bloc;b!=NIL_BLOC;b=b->next){/* Advance through heaps, marking them empty, till we get to the one that B is in. */while(heap){if(heap->bloc_start<=b->data&&b->data<=heap->end)break;heap=heap->next;/* We know HEAP is not null now, because there has to be space for bloc B. */heap->first_bloc=NIL_BLOC;heap->last_bloc=NIL_BLOC;heap->free=heap->bloc_start;}/* Update HEAP's status for bloc B. */heap->free=b->data+b->size;heap->last_bloc=b;if(heap->first_bloc==NIL_BLOC)heap->first_bloc=b;/* Record that B is in HEAP. */b->heap=heap;}/* If there are any remaining heaps and no blocs left, mark those heaps as empty. */heap=heap->next;while(heap){heap->first_bloc=NIL_BLOC;heap->last_bloc=NIL_BLOC;heap->free=heap->bloc_start;heap=heap->next;}}/* Resize BLOC to SIZE bytes. This relocates the blocs that come after BLOC in memory. */staticintresize_bloc(bloc,size)bloc_ptrbloc;SIZEsize;{registerbloc_ptrb;heap_ptrheap;POINTERaddress;SIZEold_size;/* No need to ever call this if arena is frozen, bug somewhere! */if(r_alloc_freeze_level)abort();if(bloc==NIL_BLOC||size==bloc->size)return1;for(heap=first_heap;heap!=NIL_HEAP;heap=heap->next){if(heap->bloc_start<=bloc->data&&bloc->data<=heap->end)break;}if(heap==NIL_HEAP)abort();old_size=bloc->size;bloc->size=size;/* Note that bloc could be moved into the previous heap. */address=(bloc->prev?bloc->prev->data+bloc->prev->size:first_heap->bloc_start);while(heap){if(heap->bloc_start<=address&&address<=heap->end)break;heap=heap->prev;}if(!relocate_blocs(bloc,heap,address)){bloc->size=old_size;return0;}if(size>old_size){for(b=last_bloc;b!=bloc;b=b->prev){if(!b->variable){b->size=0;b->data=b->new_data;}else{safe_bcopy(b->data,b->new_data,b->size);*b->variable=b->data=b->new_data;}}if(!bloc->variable){bloc->size=0;bloc->data=bloc->new_data;}else{safe_bcopy(bloc->data,bloc->new_data,old_size);bzero(bloc->new_data+old_size,size-old_size);*bloc->variable=bloc->data=bloc->new_data;}}else{for(b=bloc;b!=NIL_BLOC;b=b->next){if(!b->variable){b->size=0;b->data=b->new_data;}else{safe_bcopy(b->data,b->new_data,b->size);*b->variable=b->data=b->new_data;}}}update_heap_bloc_correspondence(bloc,heap);break_value=(last_bloc?last_bloc->data+last_bloc->size:first_heap->bloc_start);return1;}/* Free BLOC from the chain of blocs, relocating any blocs above it. This may return space to the system. */staticvoidfree_bloc(bloc)bloc_ptrbloc;{heap_ptrheap=bloc->heap;if(r_alloc_freeze_level){bloc->variable=(POINTER*)NIL;return;}resize_bloc(bloc,0);if(bloc==first_bloc&&bloc==last_bloc){first_bloc=last_bloc=NIL_BLOC;}elseif(bloc==last_bloc){last_bloc=bloc->prev;last_bloc->next=NIL_BLOC;}elseif(bloc==first_bloc){first_bloc=bloc->next;first_bloc->prev=NIL_BLOC;}else{bloc->next->prev=bloc->prev;bloc->prev->next=bloc->next;}/* Update the records of which blocs are in HEAP. */if(heap->first_bloc==bloc){if(bloc->next!=0&&bloc->next->heap==heap)heap->first_bloc=bloc->next;elseheap->first_bloc=heap->last_bloc=NIL_BLOC;}if(heap->last_bloc==bloc){if(bloc->prev!=0&&bloc->prev->heap==heap)heap->last_bloc=bloc->prev;elseheap->first_bloc=heap->last_bloc=NIL_BLOC;}relinquish();free(bloc);}/* Interface routines. *//* Obtain SIZE bytes of storage from the free pool, or the system, as necessary. If relocatable blocs are in use, this means relocating them. This function gets plugged into the GNU malloc's __morecore hook. We provide hysteresis, never relocating by less than extra_bytes. If we're out of memory, we should return zero, to imitate the other __morecore hook values - in particular, __default_morecore in the GNU malloc package. */POINTERr_alloc_sbrk(size)longsize;{registerbloc_ptrb;POINTERaddress;if(!r_alloc_initialized)r_alloc_init();if(!use_relocatable_buffers)return(*real_morecore)(size);if(size==0)returnvirtual_break_value;if(size>0){/* Allocate a page-aligned space. GNU malloc would reclaim an extra space if we passed an unaligned one. But we could not always find a space which is contiguous to the previous. */POINTERnew_bloc_start;heap_ptrh=first_heap;SIZEget=ROUNDUP(size);address=(POINTER)ROUNDUP(virtual_break_value);/* Search the list upward for a heap which is large enough. */while((char*)h->end<(char*)MEM_ROUNDUP((char*)address+get)){h=h->next;if(h==NIL_HEAP)break;address=(POINTER)ROUNDUP(h->start);}/* If not found, obtain more space. */if(h==NIL_HEAP){get+=extra_bytes+page_size;if(!obtain(address,get))return0;if(first_heap==last_heap)address=(POINTER)ROUNDUP(virtual_break_value);elseaddress=(POINTER)ROUNDUP(last_heap->start);h=last_heap;}new_bloc_start=(POINTER)MEM_ROUNDUP((char*)address+get);if(first_heap->bloc_start<new_bloc_start){/* This is no clean solution - no idea how to do it better. */if(r_alloc_freeze_level)returnNIL;/* There is a bug here: if the above obtain call succeeded, but the relocate_blocs call below does not succeed, we need to free the memory that we got with obtain. *//* Move all blocs upward. */if(!relocate_blocs(first_bloc,h,new_bloc_start))return0;/* Note that (POINTER)(h+1) <= new_bloc_start since get >= page_size, so the following does not destroy the heap header. */for(b=last_bloc;b!=NIL_BLOC;b=b->prev){safe_bcopy(b->data,b->new_data,b->size);*b->variable=b->data=b->new_data;}h->bloc_start=new_bloc_start;update_heap_bloc_correspondence(first_bloc,h);}if(h!=first_heap){/* Give up managing heaps below the one the new virtual_break_value points to. */first_heap->prev=NIL_HEAP;first_heap->next=h->next;first_heap->start=h->start;first_heap->end=h->end;first_heap->free=h->free;first_heap->first_bloc=h->first_bloc;first_heap->last_bloc=h->last_bloc;first_heap->bloc_start=h->bloc_start;if(first_heap->next)first_heap->next->prev=first_heap;elselast_heap=first_heap;}bzero(address,size);}else/* size < 0 */{SIZEexcess=(char*)first_heap->bloc_start-((char*)virtual_break_value+size);address=virtual_break_value;if(r_alloc_freeze_level==0&&excess>2*extra_bytes){excess-=extra_bytes;first_heap->bloc_start=(POINTER)MEM_ROUNDUP((char*)first_heap->bloc_start-excess);relocate_blocs(first_bloc,first_heap,first_heap->bloc_start);for(b=first_bloc;b!=NIL_BLOC;b=b->next){safe_bcopy(b->data,b->new_data,b->size);*b->variable=b->data=b->new_data;}}if((char*)virtual_break_value+size<(char*)first_heap->start){/* We found an additional space below the first heap */first_heap->start=(POINTER)((char*)virtual_break_value+size);}}virtual_break_value=(POINTER)((char*)address+size);break_value=(last_bloc?last_bloc->data+last_bloc->size:first_heap->bloc_start);if(size<0)relinquish();returnaddress;}/* Allocate a relocatable bloc of storage of size SIZE. A pointer to the data is returned in *PTR. PTR is thus the address of some variable which will use the data area. The allocation of 0 bytes is valid. In case r_alloc_freeze is set, a best fit of unused blocs could be done before allocating a new area. Not yet done. If we can't allocate the necessary memory, set *PTR to zero, and return zero. */POINTERr_alloc(ptr,size)POINTER*ptr;SIZEsize;{registerbloc_ptrnew_bloc;if(!r_alloc_initialized)r_alloc_init();new_bloc=get_bloc(MEM_ROUNDUP(size));if(new_bloc){new_bloc->variable=ptr;*ptr=new_bloc->data;}else*ptr=0;return*ptr;}/* Free a bloc of relocatable storage whose data is pointed to by PTR. Store 0 in *PTR to show there's no block allocated. */voidr_alloc_free(ptr)registerPOINTER*ptr;{registerbloc_ptrdead_bloc;if(!r_alloc_initialized)r_alloc_init();dead_bloc=find_bloc(ptr);if(dead_bloc==NIL_BLOC)abort();free_bloc(dead_bloc);*ptr=0;#ifdef emacsrefill_memory_reserve();#endif}/* Given a pointer at address PTR to relocatable data, resize it to SIZE. Do this by shifting all blocks above this one up in memory, unless SIZE is less than or equal to the current bloc size, in which case do nothing. In case r_alloc_freeze is set, a new bloc is allocated, and the memory copied to it. Not very efficient. We could traverse the bloc_list for a best fit of free blocs first. Change *PTR to reflect the new bloc, and return this value. If more memory cannot be allocated, then leave *PTR unchanged, and return zero. */POINTERr_re_alloc(ptr,size)POINTER*ptr;SIZEsize;{registerbloc_ptrbloc;if(!r_alloc_initialized)r_alloc_init();if(!*ptr)returnr_alloc(ptr,size);if(!size){r_alloc_free(ptr);returnr_alloc(ptr,0);}bloc=find_bloc(ptr);if(bloc==NIL_BLOC)abort();if(size<bloc->size){/* Wouldn't it be useful to actually resize the bloc here? *//* I think so too, but not if it's too expensive... */if((bloc->size-MEM_ROUNDUP(size)>=page_size)&&r_alloc_freeze_level==0){resize_bloc(bloc,MEM_ROUNDUP(size));/* Never mind if this fails, just do nothing... *//* It *should* be infallible! */}}elseif(size>bloc->size){if(r_alloc_freeze_level){bloc_ptrnew_bloc;new_bloc=get_bloc(MEM_ROUNDUP(size));if(new_bloc){new_bloc->variable=ptr;*ptr=new_bloc->data;bloc->variable=(POINTER*)NIL;}elsereturnNIL;}else{if(!resize_bloc(bloc,MEM_ROUNDUP(size)))returnNIL;}}return*ptr;}/* Disable relocations, after making room for at least SIZE bytes of non-relocatable heap if possible. The relocatable blocs are guaranteed to hold still until thawed, even if this means that malloc must return a null pointer. */voidr_alloc_freeze(size)longsize;{if(!r_alloc_initialized)r_alloc_init();/* If already frozen, we can't make any more room, so don't try. */if(r_alloc_freeze_level>0)size=0;/* If we can't get the amount requested, half is better than nothing. */while(size>0&&r_alloc_sbrk(size)==0)size/=2;++r_alloc_freeze_level;if(size>0)r_alloc_sbrk(-size);}voidr_alloc_thaw(){if(!r_alloc_initialized)r_alloc_init();if(--r_alloc_freeze_level<0)abort();/* This frees all unused blocs. It is not too inefficient, as the resize and bcopy is done only once. Afterwards, all unreferenced blocs are already shrunk to zero size. */if(!r_alloc_freeze_level){bloc_ptr*b=&first_bloc;while(*b)if(!(*b)->variable)free_bloc(*b);elseb=&(*b)->next;}}/* The hook `malloc' uses for the function which gets more space from the system. */externPOINTER(*__morecore)();/* Initialize various things for memory allocation. */staticvoidr_alloc_init(){if(r_alloc_initialized)return;r_alloc_initialized=1;real_morecore=__morecore;__morecore=r_alloc_sbrk;first_heap=last_heap=&heap_base;first_heap->next=first_heap->prev=NIL_HEAP;first_heap->start=first_heap->bloc_start=virtual_break_value=break_value=(*real_morecore)(0);if(break_value==NIL)abort();page_size=PAGE;extra_bytes=ROUNDUP(50000);/* Give GNU malloc's morecore some hysteresis so that we move all the relocatable blocks much less often. */__malloc_extra_blocks=64;first_heap->end=(POINTER)ROUNDUP(first_heap->start);/* The extra call to real_morecore guarantees that the end of the address space is a multiple of page_size, even if page_size is not really the page size of the system running the binary in which page_size is stored. This allows a binary to be built on a system with one page size and run on a system with a smaller page size. */(*real_morecore)(first_heap->end-first_heap->start);/* Clear the rest of the last page; this memory is in our address space even though it is after the sbrk value. *//* Doubly true, with the additional call that explicitly adds the rest of that page to the address space. */bzero(first_heap->start,first_heap->end-first_heap->start);virtual_break_value=break_value=first_heap->bloc_start=first_heap->end;use_relocatable_buffers=1;}#ifdef DEBUG#include <assert.h>voidr_alloc_check(){intfound=0;heap_ptrh,ph=0;bloc_ptrb,pb=0;if(!r_alloc_initialized)return;assert(first_heap);assert(last_heap->end<=(POINTER)sbrk(0));assert((POINTER)first_heap<first_heap->start);assert(first_heap->start<=virtual_break_value);assert(virtual_break_value<=first_heap->end);for(h=first_heap;h;h=h->next){assert(h->prev==ph);assert((POINTER)ROUNDUP(h->end)==h->end);#if 0 /* ??? The code in ralloc.c does not really try to ensure the heap start has any sort of alignment. Perhaps it should. */ assert ((POINTER) MEM_ROUNDUP (h->start) == h->start);#endifassert((POINTER)MEM_ROUNDUP(h->bloc_start)==h->bloc_start);assert(h->start<=h->bloc_start&&h->bloc_start<=h->end);if(ph){assert(ph->end<h->start);assert(h->start<=(POINTER)h&&(POINTER)(h+1)<=h->bloc_start);}if(h->bloc_start<=break_value&&break_value<=h->end)found=1;ph=h;}assert(found);assert(last_heap==ph);for(b=first_bloc;b;b=b->next){assert(b->prev==pb);assert((POINTER)MEM_ROUNDUP(b->data)==b->data);assert((SIZE)MEM_ROUNDUP(b->size)==b->size);ph=0;for(h=first_heap;h;h=h->next){if(h->bloc_start<=b->data&&b->data+b->size<=h->end)break;ph=h;}assert(h);if(pb&&pb->data+pb->size!=b->data){assert(ph&&b->data==h->bloc_start);while(ph){if(ph->bloc_start<=pb->data&&pb->data+pb->size<=ph->end){assert(pb->data+pb->size+b->size>ph->end);break;}else{assert(ph->bloc_start+b->size>ph->end);}ph=ph->prev;}}pb=b;}assert(last_bloc==pb);if(last_bloc)assert(last_bloc->data+last_bloc->size==break_value);elseassert(first_heap->bloc_start==break_value);}#endif /* DEBUG */